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Table 2 Synthesis of THDPP’s (5a–m) in water in room temperature
figure c

From: Catalyst-free synthesis of tetrahydrodipyrazolopyridines via an one-pot tandem and green pseudo-six-component reaction in water

Entry R Product Time
(min)
Yield
(%)b
M.P
(°C)
Lit. M.P. (C) [Reference]
1 4-Cl 5a 45 98 244–246 254–256 [19]
2 4-NO2 5b 60 96 274–276 278–283 [19]
3 3-NO2 5c 50 98 268–270 282–284 [20]
4 4-OH 5d 80 96 266–268 267–268 [21]
5 4-Br 5e 75 96 222–224 221–224 [19]
6 2-Cl 5f 105 94 162–164 164–165 [22]
7 4-N(CH3)2 5g 90 85 238–239 240–242 [19]
8 4-Me 5h 180 95 240–242 241–243 [20]
9 4-F 5i 75 97 255–257 258–260 [18]
10 4-OCH3 5j 90 98 187–189 188–190 [20]
11 3-OMe-4-OH 5k 90 98 256–258 256–258 [20]
12 3,4-(OH)2 5l 90 83 208–210 208–210 [20]
13 4-CHO 5 m 120 91  > 300°  > 300° [23]
  1. Reaction conditions: hydrazine hydrate (2 mmol), ethyl acetoacetate (2 mmol), 4-chloro benzaldehyde (1 mmol) and ammonium acetate (4 mmol), water (3 mL) at room temperature